Electron transfer in the quenching of protonated triplet thionine and methylene blue by ground state thionine

Conference · Thu Jan 01 04:00:00 UTC 1981 · Proc. Annu. Meet. - Am. Sect. Int. Sol. Energy Soc.; (United States)

OSTI ID:5861476

Kamat, P V; Lichtin, N N

Use of thiazine dyes, e.g., thionine and methylene blue, in the conversion of light energy into electrical energy has been studied extensively in recent years. Despite continuing efforts to improve the performance of photogalvanic cells, the highest reported engineering efficiency for photogalvanic conversion of sunlight into electricity is still less than 0.1%. One of the proposed steps to increase efficiency is to employ high concentrations of light-absorbing dye, e.g., 0.1 M. However, use of such high concentrations of dye may lead to wastage of absorbed quantum energy via a variety of processes, one of which is quenching of triplet dye by ground-state dye. A study of such ground-state quenching of protonated triplet methylene blue, /sup 3/MBH/sup 2 +/, with efficiency of net electron transfer in quenching, F/sub 1/, less than 0.5 was reported previously. Quenching without net electron-transfer inevitably reduces the conversion efficiency of photogalvanic cells. The results of a laser flash-photolytic, kinetic spectrometric study of kinetics and mechanism of quenching of protonated triplet thionine, /sup 3/TH/sub 2//sup 2 +/, and /sup 3/MBH/sup 2 +/ by ground-state thionine, TH/sup +/, in water, aqueous CH/sub 3/CN and aqueous ethanol are presented.

• Research Organization: Boston Univ., MA
• OSTI ID: 5861476
• Report Number(s): CONF-810509-(Vol.1)
• Conference Information: Journal Name: Proc. Annu. Meet. - Am. Sect. Int. Sol. Energy Soc.; (United States) Journal Volume: 4.1
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
ALCOHOLS
AMINES
ANTI-INFECTIVE AGENTS
ANTIMICROBIAL AGENTS
AZINES
CHEMICAL REACTION KINETICS
CHLORIDES
CHLORINE COMPOUNDS
DRUGS
DYES
ELECTROCHEMICAL CELLS
ELECTRON TRANSFER
EQUIPMENT
ETHANOL
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
KINETICS
METHYLENE BLUE
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHENOTHIAZINES
PHOTOELECTROCHEMICAL CELLS
PHOTOGALVANIC CELLS
REACTION KINETICS
SCINTILLATION QUENCHING
SOLAR EQUIPMENT
THIONINE